Fix: Futile Attempt to Implement Image-Dedupe (#55)

src/core/cover/coverResolver.ts

@@ -0,0 +1,95 @@
+import { store }                    from "@store/state.svelte";
+import { searchWithScore }          from "@core/algorithms/search";
+import { getHash, areDuplicates }   from "@core/cover/coverHash";
+
+type CoverManga = { id: number; thumbnailUrl: string; source?: { displayName: string } | null };
+
+export type CoverCandidate = {
+  mangaId:  number;
+  url:      string;
+  label:    string;
+  isActive: boolean;
+};
+
+const FUZZY_SCORE_THRESHOLD = 0.65;
+
+function normalizeUrl(url: string): string {
+  try {
+    const u = new URL(url);
+    u.search = "";
+    return u.href.toLowerCase();
+  } catch {
+    return url.toLowerCase();
+  }
+}
+
+export function resolvedCover(mangaId: number, ownUrl: string): string {
+  return store.settings.mangaPrefs?.[mangaId]?.coverUrl ?? ownUrl;
+}
+
+function fuzzyMatchIds(
+  mangaId:  number,
+  title:    string,
+  mangaById: Map<number, CoverManga & { title: string }>,
+): number[] {
+  const results = searchWithScore(
+    [...mangaById.values()].filter(m => m.id !== mangaId),
+    title,
+    m => m.title,
+  );
+  return results
+    .filter(r => r.score >= FUZZY_SCORE_THRESHOLD)
+    .map(r => r.item.id);
+}
+
+export function coverCandidatesSync(
+  mangaId:   number,
+  title:     string,
+  ownUrl:    string,
+  mangaById: Map<number, CoverManga & { title: string }>,
+): CoverCandidate[] {
+  const linkedIds  = store.getLinkedMangaIds(mangaId);
+  const fuzzyIds   = fuzzyMatchIds(mangaId, title, mangaById);
+  const current    = store.settings.mangaPrefs?.[mangaId]?.coverUrl ?? ownUrl;
+
+  const allIds = Array.from(new Set([...linkedIds, ...fuzzyIds]));
+
+  const raw: { mangaId: number; url: string; label: string }[] = [
+    { mangaId, url: ownUrl, label: "This source" },
+    ...allIds.flatMap(id => {
+      const m = mangaById.get(id);
+      return m ? [{ mangaId: m.id, url: m.thumbnailUrl, label: m.source?.displayName ?? `ID ${m.id}` }] : [];
+    }),
+  ];
+
+  const seen = new Set<string>();
+  return raw
+    .filter(c => {
+      const key = normalizeUrl(c.url);
+      if (seen.has(key)) return false;
+      seen.add(key);
+      return true;
+    })
+    .map(c => ({ ...c, isActive: normalizeUrl(c.url) === normalizeUrl(current) }));
+}
+
+export async function dedupeByImage(candidates: CoverCandidate[]): Promise<CoverCandidate[]> {
+  const hashes = await Promise.all(candidates.map(c => getHash(c.url)));
+
+  const groups: number[][] = [];
+
+  for (let i = 0; i < candidates.length; i++) {
+    const hi = hashes[i];
+    const existing = hi
+      ? groups.find(g => { const hj = hashes[g[0]]; return hj ? areDuplicates(hi, hj) : false; })
+      : undefined;
+    if (existing) existing.push(i);
+    else groups.push([i]);
+  }
+
+  return groups.map(group => {
+    const active = group.find(i => candidates[i].isActive) ?? group[0];
+    const labels = [...new Set(group.map(i => candidates[i].label))];
+    return { ...candidates[active], label: labels.join(" · ") };
+  });
+}